High Speed Steel

PM M-48

PM M-48 High Speed Steel Data Sheet

PM M-48 is a tungsten type super high speed steel hardenable to RC 68-69. It contains high vanadium for excellent abrasion resistance and cobalt for excellent red hardness. PM M-48 is ideal for special purpose cutting tools requiring super high hardness and red hardness, excellent wear resistance and good toughness.

Chemical Composition

Carbon	1.50%
Molybdenum	5.25%
Chromium	3.75%
Cobalt	8.50%
Vanadium	3.10%
Tungsten	9.75%
Sulfur	0.07%

Typical Applications

Broaches		Milling Cutters
Gear Hobs		Tool Bits
Taps		End Mills
Shaper Cutters		High Hardness Forming Tools

High Speed Steel Comparison Chart

Thermal Treatments

Preheat : 1500/1550F (820/845C), equalize, Second preheating stage at 1800/1850F (1010/1040C)recommended for vacuum or atmosphere hardening. equalize.

Austenize : 2100/2200F (1150/1205C), 30/45 minutes at temperature. Standard recommendation to achieve RC 67-69 after tempering is to use 2150/2175F (1175/1190C)

Quench : Salt, oil or atmosphere quench to 1000-1100F(540-595C), equalize, then air cool to below 125F(50C) or hand warm. A fast quench rate from 1850 (1010C) through 1100F(595C) range is critical to achieve optimum heat treat results.

Temper : 1000F (540C) minimum, hold 2 hours at temperature, air cool. Triple tempering is required, quadruple tempering is recommended.

Cryogenic Treating : Refrigeration treatments may improve long term dimensional stability by transforming retained austenite. Refrigeration treatments should generally be performed after the first temper, and must be followed by a temper.

Hardening Data

Temperature		2100F	2125F	2150F	2175F	2200F
°C	°F	(1150C)	(1165C)	(1175C)	(1190C)	(1205C)
As Quenched		68	68	67	66.5	66.5
540	1000	67	67.5	68	68.5	69
OPTIMUM FOR MAXIMUM TOUGHNESS AND EFFECTIVE STRESS-RELIEVING
550	1025	66.5	67	67.5	68	68.5
565	1050	65.5	66.5	67	67.5	68
595	1100	63	64	65	66	66.5
620	1150	59	60	51.5	63	64
650	1200	53	55	57	59	60

NOTE A: RESULTS MAY VARY WITH HARDENING METHOD AND SECTION SIZE. SALT OR OIL QUENCHING WILL GIVE MAXIMUM RESPONSE. VACUUM OR ATMOSPHERE COOLING MAY RESULT IN UP TO 1-2 HRC POINTS LOWER.
MINIMUM TIME AT AUST TEMP (MINS)	10	10	5	5	3
MINIMUM NUMBER OF TEMPERS (2 HRS)	3	3	3	4	4

Surface Treatments

PM M-48 can be nitrided, steam tempered or titanium-nitride coated if desired. If the CVD TiN treatment is used, care is required in vacuum hardening.

Annealing

Heat to 1600F (870C), hold 2 hours, slow cool 30F (15C)/hour maximum) to 1000F (540C), then furnace or air cool.

Typical annealed hardness: 285/311 BHN.

Stress Relieving

Annealed Material: Heat to 1100/1300F(595/740C), hold two hours, cool in still air.
Hardened Material: Heat to 25F(15C) below original tempering temperature, or 1000F (540C)minimum, hold two hours, cool in still air.

Welding

Welding of PM M-48 is generally not recommended due to the fine-grain microstructure produced by the PM process. If weld repair must be performed, use air hardening tool steel filler material.

Annealed Material:Preheat 1000/1100F(540/595C), maintain over 1000F(540C) during welding. Reanneal or temper 1550F(845C) 6 hours after welding.

Hardened Material: Preheat to 25F(15C) below original tempering temperature (1000F(540C) minimum). Maintain above 900F(480C) during welding. Cool to 150F(65C) after welding. Temper 25F(15C) below original tempering temperature. Minimum 1000F(540C)

Physical Properties

Modulus of Elasticity	31psix10(6)	(214 GPa)
Density	0.298 lb/in3	(8255 kg/M3)
Thermal Conductivity	11.74 BTU/hr./ft./F	19 W/m/ °K)